Key Technologies Of Wood Fast Pyrolysis And Bio-oil Phenolic Resins Synthesis

Energy and materials are the basis for sustainable development of human society. It has great scientific importance and practical value to use fast pyrolysis technology of renewable biomass resources for preparing woody bio-resin materials. This paper intended for key technologies of wood fast pyrolysis and bio-oil phenolic resins synthesis. It mainly includes the design of pilot production line of biomass pyrolysis liquefaction with processing1000tonnes biomass a year, analysis and process optimization of influence factors of biomass pyrolysis liquefaction, analysis on products of biomass pyrolysis liquefaction, synthesis optimization of bio-oil phenolic resin for preparation of particle board, study on the curing mechanism and structural characterization of bio-oil phenolic resin. This paper organically combined upstream preparation of bio-oil efficiently with its downstream synthesis application. And then, much effort had been put on the key technologies of wood fast pyrolysis and bio-oil phenolic resins synthesis by technology research, improvement and innovation from the perspective of industrial application, which has important engineering practice significance. The main conclusions and innovations derived from this paper are as follows.(1) The design of pilot production line of biomass pyrolysis liquefaction with processing1000tonnes biomass a year has been finished. The pyrolysis vapor process, bio-oil process, gas heating process and cooling cycles process have been analysed theoretically and designed. The self-heating process of biomass pyrolysis liquefaction has been realized when using non-condensation of gases for circulating as a flow of carrier gas and heat source of fluidized-bed reactor.(2) Heat and power on the pilot production line of biomass pyrolysis has been calculated. The total calories in woody raw materials for pyrolysis is56kJ; The system required total power is76kW; The increment of methane is1.86kg/h. Fluidized bed reactor, cyclone separator, shell-and-tube heat exchanger, condensation system, moisture separators, buffer tank, staging, tank were designed and selected. Expermental running indicated that the key systems were compact and had excellent performance and the pilot production line ran stability and met the design requirements. (3) In order to improve the yield and content of phenols of bio-oil and bonding strength of phenol-formaldehyde resin adhesive, poplar bark was taken as raw materials for the optimum technologies of fast pyrolysis, which are:pyrolysis temperature of823K(550℃), particle size of0.3-0.45mm, Screw-feeder speed of20r/min(feeding rate of26kg/h), Streams of gas flow of25m3/h.(4) The main organic components of Poplar bio-oil are phenols, aldehydes, acids, and ketones and hydrocarbons and the relative percentage contents are33.55%,32%,14%,8.75%,8.53%and2.91%separately. The pH value of bio-oil was about3.33; The viscosity was39.7mPa-s; The water content was31.856%; The relative density was1.146g/cm3; The high calorific value was14.6MJ/kg. The PH and viscosity would change obviously. The weight-average molecular weight was572; The number-average molecular weight was211. The molecular weight of bio-oil was main distributed less than560.(5) The particle size of bio-char of Poplar was mainly in10-200μm and mostly in40-100μm. The bio-char has a certain amount of carbon content and caloric value and can be used for a kind of fuels directly. It should be further activation before using of adsorption of activated carbon because of the low methylene blue adsorption value and specific surface area. Non-condensing gas components analysis showed that it was included CO, CO2, H2, CH4and H2O and the relative percentage contents are40.16%,40.10%,7.95%,0.96%and10.84%.(6) As the increase of F/P molar ratio, the viscosity of bio-oil-phenolic resin gone up, free phenol content reduced, MOR and IB increased firstly and then reduced and formaldehyde increased significantly. As the increase of substitution rate of bio-oil, the viscosity of bio-oil-phenolic resin, free phenol content and MOR and IB reduced and formaldehyde emission increased. As the increase of NaOH/P molar ratio, the increasing trend of viscosity declined gradually, free phenol content reduced, formaldehyde emission reduced and MOR and bond strength increased firstly and then reduced. As the increase of reaction time, the viscosity of bio-oil-phenolic resin gone up, free phenol content reduced, formaldehyde emission reduced and MOR and IB increased firstly and then reduced in small scale.(7) Comprehensive consideration of the relationship between resin performance and production costs, the better technological conditions for synthesis of bio-oil-phenolic resin were F/P molar ratio of2.0, bio-oil substitution rate of35%, NaOH/P molar ratio of0.45, reaction time of50min. The optimization of synthesis technology was that the MOR and IB of BPF resin was36MPa and0.79MPa, which exceeds national standards substantially for Particle board (MOR>18MPa, IB>0.45MPa) and formaldehyde emission was0.56mg/100g, which well below the current minimum of Particle board industry standards (≤5mg/100g).(8) Analysis of bio-oil-phenolic resin and common phenolic resin using FTIR,13C-CP/MAS and GPC. It is found that the hydroxymethyl on the class structure of polyphenols of bio-oil and hydroxymethyl on structural units of phenol occurred copolycondensation reaction during the curing process. The degree of polymerization improved with the addition of bio-oil. Bio-oil components can be better embedded in the resin curing system eventually.(9) Analysis of bio-oil-phenolic resin and common phenolic resin using DSC found that the curing temperature of bio-oil-phenolic resin slightly higher than that of common phenolic resin, so more of the curing heat was needed with the addition of bio-oil. Dynamic parameters of bio-oil-phenolic resin with bio-oil substitution rate of30%has been calculated using the method of Kissinger, included activation energy of105.3kJ/mol, frequency factor of8.32×1012s-1, reaction series of0.94.